Image projector, projected image pattern, laser driver, imaging device

ABSTRACT

The present invention relates to an image projection apparatus, a projection image pattern, a laser drive apparatus and a camera apparatus fit for use with an electronic still camera for example. In the present invention, when a microcomputer  8  detects that a shutter release  9  is depressed, a focusing lens  3  is controlled so that a contrast signal obtained when a luminance signal from a camera signal processing circuit  6  is supplied to an auto focusing detection circuit  7  may become maximum. A control signal from the microcomputer  8  is supplied to a laser driver  13 , so that a laser diode  14  is driven to generate light of laser beams only while this control signal is supplied to the laser driver. The light of laser beams thus generated is further condensed into light of parallel laser beams by a condenser  15 . These parallel laser beams are applied to a hologram plate  16  and thereby diffracted. The laser beams thus diffracted are caused to interfere with each other, whereby a hologram reproduced image  17  is reproduced. This makes it possible to project a hologram reproduced image with sufficient contrast onto an object by small power consumption. Therefore, satisfactory focusing can be made in an auto focus mode of the contrast detection system or in a manual focus mode. At the same time, this apparatus can really be incorporated, for example, into a small electronic still camera with ease.

TECHNICAL FIELD

[0001] The present invention relates to an image projection apparatus, aprojection image pattern, a laser drive apparatus and a camera apparatusfit for use in an electronic still camera, for example. Particularly,the present invention relates to an image projection apparatus, aprojection image pattern, a laser drive apparatus and a camera apparatuseach of which helps focusing adjustment when a user takes a picture, forexample, in the dark.

BACKGROUND ART

[0002] When a user takes a picture by a still camera, for example, inthe dark because it is difficult for a user to visually confirm anobject, the object cannot be brought into focus by an auto focus camera,for example, of a contrast detection type. It is also difficult to bringthe object into focus in a manual focus mode. To solve this problem,there has been employed so far a method which enables an auto focusingoperation by irradiating the object with an auxiliary floodlight such asan LED. According to this method, however, when an object has lowcontrast, it used to be difficult to bring the object into focus.

[0003] On the other hand, for example, a floodlight for producing alarge output required for obtaining the brightness enough to focus onthe object consumes large electric power and thus produces such a greatdeal of heat that the floodlight cannot be used near the object.Alternatively, there is known, for example, a method in which light iscondensed by a lens to floodlight an object. However, when light iscondensed into a narrow area in order to increase the brightness of anobject, if a user takes a picture using a wide-angle lens, then afloodlighted area will be too narrow to make focusing easily.Conversely, if the floodlighted area is made so wide as corresponds tothat in the wide-angle photographing, a sufficient brightness of theobject cannot be obtained disadvantageously.

[0004] Further, while there is employed an auxiliary floodlight in whicha lens and a slit are placed in front of an LED or an electric bulb,etc. to project an image of the slit onto the object, a projected imagehas low contrast, so that satisfactory focusing is made difficult.Moreover, according to this method, light loss is unavoidably producedin the floodlight due to the slit, and hence electric power consumptionfor obtaining a necessary quantity of light is extremely large. As aresult, it is difficult for the above-mentioned auxiliary floodlight tobe incorporated into, for example, a small electronic still camera anddriven by a power supply such as a built-in battery.

[0005] Aside from these prior arts, there has been proposed an imageprojection apparatus in which an arbitrary hologram reproduced image isprojected by using, for example, a laser light source and a hologramplate. Such hologram reproduced image can enhance contrast of aprojected image. Accordingly, it is conceived that this hologramreproduced image is projected onto an object to be made use of focusing.That is to say, the detection in the manual focus mode or in the autofocus mode is performed using the hologram reproduced image that isprojected onto the object.

[0006] However, the image projection apparatus is such that a hologramplate is added to the existing so-called “laser pointer”, the structureof which is shown in FIGS. 14A and 14B, for example. Specifically, asshown in FIG. 14A, a laser light source 71 for generating light ofdiffused laser beams and a condenser 72 for converting the light ofdiffused laser beams to light of parallel laser beams are providedwithin a lens barrel 70. The light of parallel laser beams converted bythis condenser 72 is used as a laser pointer for indicating an arbitrarypoint and so on.

[0007] A hologram plate 73 is provided within a lens barrel 74 which isfitted onto the lens barrel 70. Then, when the light of parallel laserbeams is applied to this hologram plate 73, a hologram reproduced imageis formed and projected onto the object. However, in this imageprojection apparatus, the laser light source 71 and the condenser 72 areintegrated with each other as a single unit by the lens barrel 70, andthe hologram plate 73 of the lens barrel 74 is added to this unit thusformed. When the lens barrel 74, for example, is broken, there is a riskthat only the hologram plate 73 may be detached from the unit.

[0008] Accordingly, when the hologram reproduced image is projected ontothe object to be used for focusing as described above, if only thehologram plate 73 is detached from the unit and the light of parallellaser beams from the condenser 72 is directly applied to the object asshown in FIG. 14B, then the object, for example, a man will feeldiscomfort due to a dazzling light of parallel laser beams if he seesit. When the hologram plate 73 is present, the hologram reproduced imageis formed and hence light of laser beams is diffused, so that thediscomfort given to a man will be alleviated.

[0009] The present invention is made in view of the aforesaid points andthe problems to be solved is as follows: When a user takes a picture bya still camera in the dark, for example, it is difficult for the user tofocus in the auto focus mode of the contrast detection system or in themanual focus mode. On the other hand, the camera apparatus using theconventional auxiliary floodlight does not allow a satisfactory focusingto be performed. Moreover, because the conventional auxiliary floodlightconsumes large power, it cannot be incorporated into a small electronicstill camera for use.

[0010] Furthermore, the image projection apparatus using, for example,the laser light source and the hologram plate has a risk that, when thehologram plate is detached and so forth, a man as an object will feeluncomfortable very much due to a dazzling light of parallel laser beamsif he sees it.

DISCLOSURE OF INVENTION

[0011] The present invention seeks to facilitate the focalization when auser takes a picture, for example, in the dark. For this purpose, thepresent invention is arranged to project onto the object the hologramreproduced image which is obtained by using the laser light source andthe hologram plate. In this connection, there will be disclosed below animage projection apparatus, a projection image pattern, a laser driveapparatus and a camera apparatus according to the present invention.

BRIEF DESCRIPTION OF DRAWINGS

[0012]FIG. 1 is a block diagram showing an embodiment of an imageprojection apparatus and a camera apparatus according to the presentinvention.

[0013]FIG. 2 is a flow chart for explaining an operation of theembodiment.

[0014]FIG. 3 is a flow chart for explaining another operation of theembodiment.

[0015]FIG. 4 is a diagram showing an embodiment of a projection imagepattern according to the present invention.

[0016]FIG. 5 is a graph for explaining the pattern.

[0017]FIG. 6 is a flow chart showing an operation of a laser driveapparatus according to an embodiment of the present invention.

[0018]FIG. 7 is a flow chart showing an operation of a laser driveapparatus for adjusting an output of a laser light source according toanother embodiment of the present invention.

[0019]FIG. 8 is a diagram showing environment for the laser driveapparatus to adjust the output of the laser light source.

[0020]FIG. 9 is a block diagram showing a specific circuit of the laserdrive apparatus according to an embodiment of the present invention.

[0021]FIG. 10 is a flow chart showing an operation of a laser driveapparatus according to still another embodiment of the presentinvention.

[0022]FIGS. 11A and 11B are waveform diagrams of a pulse signal forexplaining a laser drive apparatus according to yet another embodimentof the present invention.

[0023]FIGS. 12A and 12B are specific structure diagrams of an imageprojection apparatus and a camera apparatus according to the presentinvention.

[0024]FIG. 13 is a diagram for explaining the above embodiments of thepresent invention.

[0025]FIGS. 14A and 14B are structure diagrams of conventional imageprojection apparatus.

BEST MODE FOR CARRYING OUT THE INVENTION

[0026] An image projection apparatus, a projection image pattern, alaser drive apparatus and a camera apparatus according to the presentinvention will be described below with reference to the drawings, FIG. 1of which is a block diagram showing structures of an image projectionapparatus and a camera apparatus according to an embodiment of thepresent invention.

[0027] Referring to FIG. 1, image light from an object (not shown), forexample, is condensed through a main lens 1, a zoom lens 2 and afocusing lens 3 and an object image is brought into focus on a chargecoupled device (hereinafter abbreviated to “CCD”) 4 serving as an imagepickup means. This object image is photoelectrically converted by theCCD 4 and further converted into a digital signal by a sample/hold andgain control (hereinafter abbreviated to “S/H & AGC) circuit 5.

[0028] This digital signal is further converted into a chrominancesignal and a luminance signal by a camera signal processing circuit 6and then outputted to a signal recording system, not shown. Theluminance signal from this camera signal processing circuit 6 issupplied to an auto focusing (hereinafter abbreviated to “AF”) detectioncircuit 7, in which a contrast signal necessary for AF is generatedusing this luminance signal. Then, the contrast signal thus generated issupplied to a microcomputer (hereinafter abbreviated to “micon”) 8 foruse in control operations.

[0029] Thus, if the micon 8 detects that a shutter release 9, forexample, is half depressed, then the micon controls the focusing lens 3so as to make the above-mentioned contrast signal maximum in level forAF operation. The focusing lens 3 may be controlled by sending an amountsignal to a motor driver circuit 10 for driving a focus motor 11.Similarly, the zoom lens 2 may be controlled by sending an amountcontrolling signal to the motor driver circuit 10 for driving a zoommotor 12.

[0030] A control signal is supplied from the micon 8 to a laser driver13, whereby a laser diode 14 is driven to generate light of laser beamsonly while this control signal is supplied from the micon to the laserdriver. The light of laser beams thus generated is condensed by acondenser 15 into light of parallel laser beams and the light ofparallel laser beams is applied to a hologram plate 16, in which thelight of parallel laser beams is diffracted by a hologram provided inthe hologram plate 16. Then, the laser beams thus diffracted are causedto interfere with each other, thereby making a hologram reproduced image17 reproduced.

[0031] As a result, this hologram reproduced image 17 can be projectedonto the object which lies , for example, in the optical axis directionof the main lens 1. In this case, if the hologram reproduced image 17 iscomposed of segments, then an area where the image is projected can bedecreased as compared with a projection range. Thus, an image with highcontrast can be projected to increase illuminance of the object. Inother words, by projecting the image with high contrast onto the object,satisfactory focusing can be done with ease.

[0032] Additionally, the means (apparatus) itself for projecting theabove-mentioned hologram reproduced image 17 is readily available as anauxiliary device for use with the existing laser pointer, for example,which apparatus can easily be formed by applying such device thereto.Because the laser diode 14 for use with such laser pointer can be drivenwith extremely small power consumption, such laser diode can beincorporated, for example, into a small electronic still camera, and caneasily be driven by a built-in battery and the like.

[0033] There is further provided a manual switch 18 for controlling amanner in which the hologram reproduced image 17 is projected onto theobject. When this manual switch 18 is operated, a high potential signalis supplied to the micon 8. Further, a control signal from the micon 8is supplied to a flash device 19 so that the light emission of the flashdevice 19 may be controlled by this control signal as needed. Moreover,data corresponding to measured values and controlled values generatedwithin the micon 8 are stored in a nonvolatile memory (e.g., EEPROM) 20.

[0034]FIG. 2 shows a flow chart of exemplary processings executed whenthe auto focusing operation is performed by the above-mentionedapparatus. Specifically, in FIG. 2, following the start of operation, itis first determined at a step [1] whether or not the shutter release 9is half depressed. If it is not depressed (No), then this step [1] isrepeated. If it is determined at the step [1] that the shutter release 9is depressed (Yes), then the laser diode 14 is driven at a step [2] tostart the projection of laser beams.

[0035] At a step [3], the AF operation is performed and it is determinedat a step [4] whether or not the AF operation is over. If the AFoperation is not over (No), then the steps [2], [3] are repeated. If itis determined at the step [4] that the AF operation is over (Yes), thenthe laser diode 14 is deactivated to halt the projection of light oflaser beams. At a step [6], for example, the flash device is activatedto capture an image (photograph) and the processing is stopped.

[0036] The processings are executed in this manner when theabove-mentioned apparatus is applied to the auto focusing operation. Inthis case, while the AF operation is performed at the step [3], thehologram reproduced image 17 which is reproduced at the step [2] isprojected onto the object, and hence an extremely satisfactory AFoperation can be performed using this hologram reproduced image 17.Because the projection of this hologram reproduced image 17 is halted atthe step [5] when the image is captured (photographed), this hologramreproduced image will never hinder the user from taking a picture.

[0037]FIG. 3 is a flow chart showing exemplary processings executed whenthe above-mentioned apparatus is used in the manual focus mode. In thiscase, for example, when the manual switch 18 of the above-mentionedapparatus is operated, the processing is started. Following the start ofoperation, at a step [11], the laser diode 14 is driven first to startthe projection of light of laser beams. It is determined at the nextstep [12] whether or not the shutter release 9 is half depressed.

[0038] If it is determined at the step [12] that the shutter release 9is not depressed (No), then the manual focus mode is not over, and hencethe steps [11], [12] are repeated. On the other hand, if the manualfocus mode is over and it is determined at the step [12] that theshutter release 9 is depressed (Yes), then the laser diode 14 isdeactivated to halt the projection of light of laser beams at a step[13]. Then, an image is captured (photographed) at a step [14] and theprocessing is stopped.

[0039] The processings are executed in this manner, when theabove-mentioned apparatus is used in the manual focus mode. In thiscase, because the hologram reproduced image 17 which is reproduced atthe step [11] is projected onto the object, a user can make an extremelysatisfactory manual focusing by visually confirming this hologramreproduced image 17. Because this hologram reproduced image 17 is turnedoff at the step [13] when the image is captured (photographed), thishologram reproduced image will never hinder the user from taking apicture.

[0040] Accordingly, in this embodiment, because the hologram reproducedimage obtained by using the laser light source and the hologram plate isprojected onto the object, the hologram reproduced image havingsufficient contrast can be projected onto the object by small powerconsumption. Thus, satisfactory focusing can be done in the auto focusmode of the contrast detection system or in the manual focus mode. Atthe same time, this apparatus can easily be incorporated into, forexample, a small electronic still camera.

[0041] As described above, when a user takes a picture by a stillcamera, for example, in the dark, it is difficult for the user to focusin the auto focus mode of the contrast detection system or in the manualfocus mode. On the other hand, the user not can make sufficient focusingwith the camera apparatus using the conventional auxiliary floodlight.Furthermore, the conventional auxiliary floodlight consuming a largeamount of electric power cannot be incorporated into a small electricstill camera or the like. According to the present invention, theseproblems can be overcome with ease.

[0042] In the above-mentioned apparatus, as the projection image patternof the hologram reproduced image for use in projection, such one shownin FIG. 4 is used, for example. FIG. 4 shows a projection image patternaccording to an embodiment of the present invention. As shown in FIG. 4,the projection image pattern is comprised of at least one or a pluralityof first to fifth segments A to E on each of which a predeterminednumber of light spots are arrayed in a straight line. The first segmentA is provided at the center of the projection image at an angle ofapproximately 45 degrees with horizontal and vertical axes of the imagepickup plane.

[0043] There are provided four second segments B₁ to B₄, at right angleswith the first segment A, at each vertex of a square X₁ whichcircumscribes a circle that is centered at the center of the firstsegment A and has a predetermined length of diameter a (X₁ is shown bybroken lines: the square shown by broken lines is not a projection imagepattern and hereinafter the same applies.). There are further providedeight third segments C₁ to C₈, in parallel with the first segment A, ateach vertex and at a midpoint in each side of a square X₂ (shown bybroken lines) which circumscribes a circle that is centered at thecenter of the first segment A and has a diameter 2 a twice thepredetermined length a.

[0044] There are also provided twelve fourth segments D₁ to D₁₂, atright angles with the first segment A, at each vertex and at pointstrisecting each side of a square X₃ (shown by broken lines) whichcircumscribes a circle that is centered at the centre of the firstsegment A and has a diameter 3 a three times the predetermined length a.There are further provided four fifth segments E₁ to E₄, in parallelwith the first segment A, at a midpoint of each side of a square X₄(shown by broken lines) which circumscribes a circle that is centered atthe center of the first segment A and has a diameter 4 a four times thepredetermined length a. In this way, the projection image patterncomposed of twenty-nine segments in total is formed.

[0045] In this projection image pattern, each of the segments A to E iscomprised of, for example, a fifteen light spots, arrayed in a straightline. The length of these segments A to E are set at 0.8 degree by aprojection angle, for example. The central spot of the arrayed lightspots is removed from the segment A. Specifically, a hologram for makingthe segments A to E shown in FIG. 4 into a reproduced image is found bycalculation, and the hologram based upon this calculation is provided onthe hologram plate 16.

[0046] The circle having a diameter of the predetermined length a, whichis inscribed in the square X₁, is set at, e.g. three degrees by aprojection angle. As a result, a projection angle of the circle which isinscribed in the square X₂ will be six degrees; a projection angle ofthe circle which is inscribed in the square X₃ will be nine degrees; anda projection angle of the circle which is inscribed in the square X₄will be twelve degrees. In this case, a pattern within the circle whichis inscribed, e.g. in the square X₂ is comprised of seven segmentssubstantially. Thus, an output of the laser diode 14 is set so that thequantity of heat produced when light corresponding to the seven segmentsstrikes man's retina may be less than the value of safety standards.

[0047] Therefore, according to this embodiment of the projection imagepattern, even if positions of view points are moved under the respectiveprojection angles, the heat generated will never exceed the value ofsafety standards. FIG. 5 is a graph showing the relation between themaximum powers and receptive angles with respect to heat generated,which was found by simulation. As this figure shows, even continuousgeneration of laser beams conforms to the safety standards of 1000second AEL of the class 1 of the JIS.

[0048] Moreover, according to the embodiment of the above-mentionedprojection image pattern, because the angles of adjacent segments arealternately changed from each other, the substantial space between thesegments can be reduced by the distance of half the length of thesegment. Therefore, when the detection range of the auto focus is, e.g.about 3 degrees in terms of the projection angle, even if the opticalaxis of a camera lens is not coincident with the center of theprojection image pattern, it is possible to remove such a risk that nosegment will fall within the detection range.

[0049] Furthermore, in the above embodiment of the projection imagepattern, the central light spot is removed from the light spots formingthe first segment A located at the center. As a consequence, although inthe hologram reproduced image zero-order light may sometimes begenerated at the center of the image in addition to an original imagepattern, a brightness of the light spot at the center of the firstsegment A can be prevented from being raised due to such zero-orderlight, thus allowing a satisfactory detection to be done. Even if thelight spot at the center of the first segment has no brightness, thereis no risk that the detection, e.g. in the auto focus mode may beinterfered with.

[0050] In the above-mentioned apparatus, the laser diode 14 is driven asshown in FIG. 6. That is, FIG. 6 is a flow chart showing exemplaryoperations of the laser drive apparatus according to an embodiment ofthe present invention.

[0051] Referring to FIG. 6, upon the start of operation, it is firstdetermined at a step [21] whether or not the shutter release 9 is halfdepressed. If it is depressed (Yes), it is determined at a step [22]whether or not a value of “on-counter” of an arbitrary register is lessthan 100 seconds. If the on-counter value is less than 100 seconds(Yes), a predetermined value is added to the on-counter value at a step[23]. A value of an “off-counter” of an arbitrary register is reset tozero at a step [24], and the application of light of laser beams ismaintained at a step [25].

[0052] It is further determined at a step [26] whether or not a commandfor making the power supply off is issued. If such command for makingthe power supply off is issued (Yes), then the operation comes to an end(End). If it is determined that no command for making the power supplyoff is issued (No), then the operation is returned to the step [21]. Ifit is determined at the step [21] that the shutter release 9 is notdepressed (No) and if it is determined at the step [22] that theon-counter value is not less than 100 seconds (No), then it isdetermined at a step [27] whether or not the off-counter value is lessthan five seconds.

[0053] If it is determined at the step [27] that the off-counter valueis less than five seconds (Yes), then a predetermined value is added tothe off-counter value at a step [28]. If it is determined at the step[27] that the off-counter value is not less than five seconds (No), thenthe on-counter value is reset to zero at a step [29]. After the steps[28] and [29] have been finished, the application of light of laserbeams is stopped at a step [30], and it is determined at the step [26]whether or not the command for making the power supply off should beissued.

[0054] Accordingly, in this flow chart, when the on-counter value goesgreater than 100 seconds, the application of light of laser beams isstopped. Besides, while the off-counter value remains less than fiveseconds, the on-counter value is not reset. Therefore, the apparatus isoperated so that duration in which the application of light of laserbeams is stopped may always be five seconds or longer. Thus, when thelight of laser beams, for example, is applied continuously, an output ofthe apparatus can be prevented from falling due to heat and the like. Asa consequence, it is possible to eliminate a radiator plate or the likethat has so far been used as a conventional countermeasure against theheat generation.

[0055] Moreover, in the above-mentioned apparatus, an output of thelaser diode 14 is adjusted as shown in FIGS. 7 and 8. Specifically, FIG.7 is a flow chart showing operations of the laser drive apparatus toadjust the output of the laser diode 14 according to another embodimentof the present invention. FIG. 8 shows an environment under which theoutput of the laser diode is adjusted by the laser diode driveapparatus.

[0056] Referring to FIG. 8, a screen 200 is attached to one of wallsurfaces of a box 100 the inside of which is painted in black. Theabove-mentioned camera apparatus is disposed through an opening 300provided on the wall surface opposite to the screen 200. Then, theabove-mentioned hologram reproduced image 17 is projected onto thescreen 200 and the projected image on this screen 200 is picked up bythe CCD 4. Further, the image picked-up output from this CCD 4 isdetected to adjust the output from the laser diode 14.

[0057] Referring to FIG. 7, upon the start of adjustment operation, acontrol value (DA) supplied from the micon 8 to the laser driver 13 isset as an initial value at a step [31], and the lens position is set fora distance between the camera apparatus disposed through the opening 300and the screen 200 at a step [32]. Then, at a step [33], theabove-mentioned control value (DA) is supplied through a DA output fromthe micon 8 to the laser driver 13. At a step [34], the laser diode 14starts to be driven.

[0058] In this way, the laser diode 14 is driven in accordance with thepredetermined initial value, the hologram reproduced image 17 based uponthe laser output according to this initial value being projected ontothe screen 200, and this projected image being picked up by the CCD 4.Then, at a step [35], an automatic exposure (AE) detected value (AEDATA) is detected from the image picked-up output and compared with anAE target value (AE TARGET) at a step [36]. If the two values are notequal to each other (No), then, a control value (DA) is calculated at astep [37].

[0059] Specifically, at the step [37], a new control value (DA) iscalculated from an expression, e.g. DA=DA×(AE TARGET)÷(AE DATA) and theresultant value is returned to the step [33]. This operation will berepeated until (AE DATA)=(AE TARGET) is satisfied at the step [36].Then, when the two values become equal to each other (Yes), the controlvalue (DA) is stored in the nonvolatile memory 20 at a step [38] and theoperation comes to an end.

[0060] In this manner, the value which is used to adjust the dispersionof the output from the laser diode 14 is stored in the nonvolatilememory 20. In actual practical use, the control value (DA) for drivingthe laser diode 14 is calculated based upon the value stored in thismemory 20 and taking other conditions and the like into consideration.In other words, when a user takes a picture, the stored value is readout from this memory 20 to be used as a basic value for adjustment. Atthe same time, information on stop, zoom position and the like isconsidered to control the output of the laser diode 14.

[0061] The dispersion of the output of the laser diode 14 can beadjusted by using not only the above-mentioned automatic exposuredetected value but also a contrast detected value and the like. Forexample, the control value (DA) in which the contrast detected valueforms the target value is stored in the memory. Moreover, if not onlythe above-mentioned control value but also the detected value itself andother measured values are stored in the memory 20, then such storedvalues can be used, for example, to check products in manufacturing, andalso to check their performances when services or repairs are made afterthe products have been shipped.

[0062] Accordingly, in this embodiment, the output of the laser diode 14as well as the sensitivity of the CCD 4 is adjusted. Specifically, whilethe output of the laser diode 14 according to the control value hasdispersion between individual products, the sensitivity of the CCD 4also fluctuates similarly about 20 percent. Accordingly, by adjustingthe output of the assembled camera apparatus using the image picked-upoutput of the CCD 4, the adjustment which absorbs both the dispersionand fluctuation can be carried out.

[0063] In the above-mentioned apparatus, the laser driver 13 has aspecific structure as shown in FIG. 9. FIG. 9 is a block diagram showinga specific circuit of a laser drive apparatus according to an embodimentof the present invention.

[0064] Referring to FIG. 9, the laser diode 14 is driven by a powersupply of, e.g. 5V, and other circuits including the micon 8 are drivenby a power supply of 3.2V. An output signal from the micon 8 is suppliedthrough a switching transistor 51 to a switching transistor 52 providedat the power supply line of 5V, whereby the power supply of 5V is turnedon and off. A voltage from the power supply of 5V which is turned on andoff is supplied through a transistor 53 to the laser diode 14.

[0065] A photodiode 54 is provided in the vicinity of this laser diode14. An output from this photodiode 54 is supplied to a non-invertinginput terminal of an operational amplifier 55, whereas a control valuefrom the micon 8 is supplied to an inverting input terminal of theoperational amplifier 55 through a digital-to-analog converter (DAC) 56.An output from this operational amplifier 55 is supplied to the base ofthe transistor 53. This causes the output of the laser diode 14 to beadjusted so that the output of the photodiode 54 may be kept at adesired value.

[0066] An output from the switching transistor 52 is supplied to afalling edge trigger input terminal of a monostable multivibrator(hereinafter abbreviated to “mono-multi”) 57. A Q output of thismono-multi 57 is supplied through the transistor 58 to the base of atransistor 59. A signal obtained at the collector of this transistor 59is supplied to the base of a transistor 60 connected between the 5Vpower supply line after the switching transistor 52 and the base of thetransistor 53.

[0067] Thus, in this circuit, when the laser diode 14 is continuouslydriven, for example, by the output continuously generated from theswitching transistor 52, if the time period driving this laser diodeexceeds an inverting time of the mono-multi 57, then the transistor 58is turned on, the transistor 59 being turned off and the transistor 60being turned on. As a result, the base potential of the transistor 53rises to make and the transistor 53 turned off, whereby such continuousdriving of the laser diode 14 is stopped.

[0068] Further, in the above-mentioned circuit, the output of thephotodiode 54 is supplied to an A/D converting input terminal of themicon 8 which monitors the output of the photodiode 54 to operate, forexample, as shown in FIG. 10.

[0069]FIG. 10 is a flow chart showing operations of a laser driveapparatus according to a still another embodiment of the presentinvention. Referring to FIG. 10, it is first determined at a step [41]whether or not the shutter release 9 is half depressed. If the shutterrelease is depressed (Yes), it is determined at a step [42] whether ornot a monitor voltage obtained from the photodiode 54 is equal to anarbitrary reference voltage. Then, if the monitor voltage is equal tothe reference voltage (Yes), the application of light of laser beams ismaintained at the following step [43].

[0070] On the contrary, if it is determined at the step [41] that theshutter release 9 is not depressed (No) or if it is determined at thestep [42] that the monitor voltage is not equal to the reference voltage(No), then the application of light of laser beams is stopped at a step[44]. Further, it is determined at a step [45] whether or not a commandfor making the power supply off is issued. If such command for makingthe power supply off is issued (Yes), then operations come to an end. Ifno command for making it off is issued (No), then the operation isreturned to the step [41].

[0071] Accordingly, in this embodiment, when the monitor voltageobtained from the photodiode 54 becomes equal to the arbitrary referencevoltage, the application of light of laser beams is stopped. In otherwords, the generation of light of laser beams is stopped, provided thatthe output of the monitor means exceeds an arbitrary tolerance limit.This makes it possible to remove such a risk that the laser diode 14 maybe broken or degraded in durability by an abnormal driving of the laserdiode 14.

[0072] Moreover, in the specific circuit of the laser drive apparatusshown in FIG. 9, a pulse signal, for example, as shown in FIGS. 11A and11B, is outputted from the micon 8, and the laser diode 14 is drivenaccording to this pulse signal. FIGS. 11A and 11B are waveform diagramsof pulse signals for explaining a laser drive apparatus according to yetanother embodiment of the present invention.

[0073] In this connection, the micon 8 can form a pulse signal withaccuracy, of for example, 0.8 μsec by using a counter, and can controlthe pulse width, for example, by the 0.16 msec. Moreover, a peak outputof the pulse signal can be adjusted, for example, in a range of 0 to 3mW by the 0.1 mW. Accordingly, for example, based upon the value that isstored in the memory 20 in the above-mentioned operations shown in FIG.7, the peak output of the pulse signal may be determined and the pulsewidth may be controlled in consideration of other conditions.

[0074] As shown in FIG. 11A, based upon the value stored in the memory20, the amplitude of the pulse signal is determined to be ,for example,2.5 mW. Moreover, the pulse width of each pulse may be controlleddepending on whether the built-in flash device 19 or an external flashdevice is used or not. Specifically, for example, when the built-inflash device 19 is in use, the pulse width of the pulse signal iscontrolled to be 5 msec, and when the external flash device is in use,because long distance to an object is assumed, then the pulse width iscontrolled to be 10 msec.

[0075] Furthermore, when the photography system is based upon the NTSCsystem, the micon forms the pulse signal at a cycle of 33 msecsynchronized with the frame. Because the auto focusing operation can becontrolled within 50 frames, it is designed that 50 pulses are generatedduring one operation at maximum. In this manner, the output of the laserdiode 14 is adjusted. Such operations are executed by software of themicon 8.

[0076]FIG. 11B shows a waveform of a pulse signal generated when thehalf depression of the shutter release 9 is repeated. Specifically, whena user takes a picture in a normal mode, because it takes approximatelyfour seconds to store image data in a memory device, an interval of 4seconds is inevitably formed. Even if the shutter release 9 is halfdepressed very quickly, it is arranged that an interval of one second isformed. Such operations are also executed by software of the micon 8 andintervals of 0 to 4 seconds are set by the 0.25 second, for example,based upon the values stored in the memory 20.

[0077] Moreover, when the laser diode is driven according to the pulsesignal as described above, if the inverting time of the above-mentionedmono-multi 57 shown in FIG. 9 is set to be, for example, 33 msec, thenthe generation of light of laser beams can be stopped when the fallingedge of the pulse signal does not occur. Thus, when the means foradjusting a quantity of light of laser beams malfunctions, the laserdiode 14 can be stopped from being driven. This makes it possible toremove the risk that the laser diode 14 may be damaged or less durable.

[0078] Therefore, in this embodiment, the quantity of light of laserbeams can be adjusted satisfactorily by driving the laser light sourceaccording on the pulse signal having an arbitrary pulse width. Moreover,the quantity of light of laser beams can also be adjusted by controllingthe pulse width depending on the presence or absence of the built-inflash device 19 or the external flash device. Furthermore, when themeans for adjusting the quantity of light of laser beams malfunctions,the driving of the laser diode 14 can be stopped to remove the risk thatthe laser diode 14 may be broken or less durable.

[0079] By applying the above-mentioned image projection apparatus, theprojection image pattern or the laser drive apparatus to the cameraapparatus according to the present invention, the hologram reproducedimage having a sufficient contrast can be projected onto the object withsmall power consumption, so that satisfactory focusing can be attained.At the same time, these apparatus can easily be incorporated into asmall electronic still camera and the like.

[0080] As described above, the image projection apparatus of the presentinvention comprises the laser light source for generating light of laserbeams and the hologram plate. By projecting onto the object the hologramreproduced image which is obtained by applying light of laser beams tothe hologram plate, the hologram reproduced image having good contrastcan be projected onto the object with small power consumption, thusallowing satisfactory focusing to be performed. Also, this apparatus caneasily be incorporated into a small electronic still camera and thelike.

[0081] Further, according to the projection image pattern of the presentinvention, by employing the above-mentioned pattern of FIG. 4, heatproduced can be prevented from exceeding the safety standards limit,even if the position of the view point is moved under the respectiveprojection angles. At the same time, because the substantial spacebetween the segments can be reduced by a distance which is half a lengthof the segment, even if the optical axis of the camera lens is notcoincident with the center of the projection image pattern, there can beremoved such a risk that a state in which no segment is captured withinthe detection range may occur.

[0082] Moreover, according to the laser drive apparatus of the presentinvention, because this laser drive apparatus includes the laser lightsource for generating light of laser beams and the laser light source isstopped from generating the light of laser beams for a fixed time periodor longer, on condition that the duration of emitting the light of laserbeams exceeds the predetermined time period, for example, when the lightof laser beams is applied continuously, the output can be prevented fromfalling due to heating or the like. Thus, a radiator plate that has sofar been used as a conventional countermeasure against heat generationcan be dispensed with.

[0083] Furthermore, the laser drive apparatus of the present inventionincludes the laser light source for generating light of laser beams, themeans for adjusting the quantity of light of laser beams and the camerameans, and further comprises the memory means for storing therein theadjustment value found according to an output of the camera means whichhas taken the image under previously projected light of laser beams.Thus, the output of the laser light source as well as the sensitivity ofthe camera means can be adjusted by adjusting the quantity of light oflaser beams based upon the stored adjustment value. In other words, theadjustment absorbing dispersions of the output and the sensitivity canbe carried out.

[0084] Furthermore, the laser drive apparatus of the present inventionincludes the laser light source for generating light of laser beams andthe monitor means for detecting light of laser beams, and is arranged sothat the laser light source may be stopped from generating light oflaser beams on condition that an output of the monitor means exceeds thearbitrary tolerance limit. Thus, it is possible to remove the risk thatthe laser light source may be damaged or less durable by an abnormaldriving of laser light source.

[0085] Moreover, the laser drive apparatus of the present inventionincludes the laser light source for generating light of laser beams andthe means for adjusting the quantity of light of laser beams, and isarranged so that the quantity of light of laser beams may be adjusted bydriving the laser light source using the pulse signal having thearbitrary pulse width. Thus, the quantity of light of laser beams can beadjusted satisfactorily, and also the quantity of light of laser beamscan be adjusted depending on the presence or absence of the built-inflash device, so that it is possible to remove the risk that the laserlight source may be broken or degraded in durability.

[0086] Furthermore, the camera apparatus of the present inventionincludes the projection means having the laser light source and thehologram plate, for projecting onto the object a hologram reproducedimage which is obtained by applying light of laser beams from the laserlight source to the hologram plate. Thus, the hologram reproduced imagehaving good contrast can be projected onto the object with small powerconsumption, thereby allowing satisfactory focusing to be attained. Atthe same time, this apparatus can easily be incorporated into a smallelectronic still camera or the like.

[0087] In short, the above-mentioned camera apparatus has theadvantageous effects as follows:

[0088] {circle over (1)} The focusing is enabled in the AF mode even oncondition that the illuminance of an object is low.

[0089] {circle over (2)} Even an object with low contrast can be broughtinto focus in the AF mode.

[0090] {circle over (3)} Because light of laser beams with high contrastis projected on an object, the focusing is enabled in the auto focusmode with higher accuracy than before.

[0091] {circle over (4)} The long-distance projection, which hasheretofore been difficult to be made with a conventional auxiliaryfloodlight having low output, becomes possible.

[0092] {circle over (5)} Because of a projecting efficiency severaltimes as high as that of the conventional auxiliary floodlight, alow-output projection apparatus can be used for obtaining a sufficientilluminance, so that energy consumption thereof is reduced to areciprocal of several of conventional energy consumption.

[0093] {circle over (6)} Because an effective projected area is small,it is less possible that those who are photographed will feel dazzled.

[0094] {circle over (7)} An object with low illuminance and lowcontrast, which has been hard to be brought into focus in theconventional manual focus mode, can be brought into focus with ease.

[0095] {circle over (8)} The projection compatible to both of wide-anglelens mode and telephoto lens mode, which has so far been difficult to bemade with the conventional auxiliary floodlight, becomes possible.

[0096]FIGS. 12A and 12B show specific structures of the image projectionapparatus and the camera apparatus according to the present invention.Referring to FIG. 12A, only a laser diode 14 for generating light ofdiffused laser beams is provided within a laser-support frame 21. Acondenser 15 which converts light of diffused laser beams to light ofparallel laser beams is provided within a lens-support frame 22 which isfitted on the laser-support frame 21. At the same time, a hologram plate16 is attached to the lens-support frame, e.g. by a retaining ring 23.Thus, these elements are integrally formed as a single unit.

[0097] After a clearance between the laser-support frame 21 and thelens-support frame 22 is adjusted, these laser- and lens-support frames21 and 22 are fixed by an adhesive and the like. Then, these laser- andlens-support frames 21 and 22 are attached to a predetermined positionof a camera housing 25 through a transparent acrylic cover 24. In otherwords, a window covered by the transparent acrylic cover 24 is providedat the predetermined position of the camera housing 25 and the laser-andlens-support frames 21 and 22 are attached to this transparent acryliccover 24.

[0098] As a result, when the laser diode 14 is driven in this state,light of the diffused laser beams thus generated is converted into lightof parallel laser beams by the condenser 15 and the light of parallellaser beams is applied to the hologram plate 16, thereby causing ahologram reproduced image (not shown) to be produced. Then, thishologram reproduced image is projected onto the object through thetransparent acrylic cover 24 provided at the predetermined position ofthe camera housing 25.

[0099] Accordingly, in this embodiment, the condenser 15 and thehologram plate 16 are integrated into one body unit. Thus, for example,when the lens-support frame 22 is broken as shown in FIG. 12B, both ofthe condenser 15 and the hologram plate 16 are detached from the laserdiode 14. In other words, when the lens-support frame 22 is broken andthe hologram plate 16 is detached from the laser diode, the condenser 15is also detached from the laser diode 14 at the same time.

[0100] In this case, because only the light of diffused laser beams isgenerated by the laser diode 14 from which the condenser lens 15 isdetached, even if the light of diffused laser beams is directly appliedto an object, when the object is, for example, a man, there will be norisk that a man will feel discomfort due to the dazzling light ofparallel laser beams. Therefore, according to this embodiment, even ifthe hologram plate is detached from the laser diode, there can beremoved such a risk that a man may feel discomfort due to the dazzlinglight of laser beams.

[0101] As described above, when a user takes a picture by a still camerain the dark, or the like, it is very difficult to focus in the autofocus mode of the contrast detection system or in the manual focus mode.On the other hand, the image projection apparatus employing the laserlight source and the hologram plate involves a risk that a man as anobject will feel uncomfortable very much if he sees the dazzling lightof parallel laser beams when the hologram plate is detached from thelaser diode. According to the present invention, these problems can beovercome with ease.

[0102] In the above-mentioned apparatus, as shown in FIG. 13, forexample, when a small hologram image for taking a picture in thetelephoto lens mode and a large hologram image for taking a picture inthe wide-angle lens mode are both projected onto the object at the sametime, it will be possible to make adapt for both of the wide rangeprojection and the telephotograph projection. Additionally, in FIG. 13,there are projected such hologram images that a projection angle of aninner circle is set at about 5 degrees and a projection angle of aninner circle is set at about 20 degrees. In addition, when the hologramimages are composed of fine lines, even the apparatus whose output issmall can project with sufficient brightness.

[0103] As described above, the image projection apparatus according tothe present invention comprises the laser light source for generatingthe light of diffused laser beams, the condenser for converting thelight of diffused laser beams to the light of parallel laser beams andthe hologram plate which is irradiated with the light of parallel laserbeams. Because the condenser is integrated with the hologram plate intoone body unit in the above image projection apparatus, even if thehologram plate is detached from the laser diode, there can be removedsuch a risk that a man as the object may feel discomfort due to thedazzling light of parallel laser beams.

[0104] Moreover, the above-mentioned camera apparatus includes the imageprojection apparatus which is comprised of the laser light source forgenerating the light of diffused laser beams, the condenser forconverting the light of diffused laser beams to the light of parallellaser beams and the hologram plate irradiated with the light of parallellaser beams, and in which the condenser is integrated with the hologramplate into one body single unit. Thus, by projecting onto the object thehologram reproduced image is which is obtained by applying the light ofparallel laser beams to the hologram plate, the hologram reproducedimage with sufficient contrast can be projected onto the object, wherebysatisfactory focusing can be performed. At the same time, even if thehologram plate is detached from the laser diode, there can be removedthe risk that a man as the object may feel discomfort due to thedazzling light of parallel laser beams.

[0105] As described above, according to the present invention, thefocusing can easily be adjusted when a user takes a picture in the darkor the like. The present invention is not limited to the above-describedembodiment and various modifications can be made without departing fromthe spirit of the present invention.

[0106] Thus, according to the present invention, because the imageprojection apparatus includes the laser light source for generatinglight of laser beams and the hologram plate and the hologram reproducedimage is projected onto the object, which is obtained by applying thelight of laser beams to the hologram plate, the hologram reproducedimage can be projected onto the object with sufficient contrast withsmall power consumption and satisfactory focusing can be performed. Atthe same time, this apparatus can easily be incorporated into , forexample, a small electronic still camera.

[0107] Moreover, according to the present invention, because the autofocusing operation is carried out using the hologram reproduced imageprojected onto the object, an extremely satisfactory AF operation can becarried out.

[0108] Moreover, according to the present invention, because the imageprojection apparatus includes the operation means for projecting thehologram reproduced image in the manual focusing operation, the user canexecute an extremely good manual focusing operation by visuallyconfirming the hologram reproduced image, and this hologram reproducedimage can never hinder the user from taking a picture.

[0109] Furthermore, according to the present invention, because theimage projection apparatus includes the laser light source forgenerating the light of diffused laser beams, the condenser forconverting the light of diffused laser beams to the light of parallellaser beams and the hologram plate which is irradiated with the light ofparallel laser beams, and the condenser and the hologram plate areintegrated with each other into one body unit, even if the hologramplate is detached from the laser diode, it will be possible to removethe risk that a man as the object may feel discomfort due to thedazzling light of parallel laser beams.

[0110] Moreover, according to the present invention, because thehologram reproduced image is projected onto the object, which isobtained by applying the light of parallel laser beams to the hologramplate, focusing can be carried out satisfactorily by projecting thehologram reproduced image with sufficient contrast onto the object. Atthe same time, even if the hologram plate is detached from the laserdiode, it will be possible to remove the risk that a man as the objectmay feel discomfort due to the dazzling light of parallel laser beams.

[0111] Moreover, according to the present invention, because the autofocusing operation is carried out using the hologram reproduced imageprojected onto the object, the extremely good AF operation can becarried out. At the same time, even if the hologram plate is detachedfrom the laser diode, it will be possible to remove the risk that a manas the object may feel discomfort due to the dazzling light of parallellaser beams.

[0112] Furthermore, according to the present invention, because theabove-mentioned pattern shown in FIG. 4 is employed, even if theposition of the view point is moved under the respective projectionangles, no heat is produced beyond the safety standards limit, and thesubstantial space between the segments can be reduced by the distanceequal to half of the length of the segment. Thus, even if the opticalaxis of the camera lens does not coincide with the center of theprojected image pattern, it is possible to remove such a risk that astate in which no segment is captured within the detection range mayhappen.

[0113] Moreover, according to the present invention, because the centrallight spot is eliminated from a predetermined number of the light spotsforming the first segment, the luminance of the central light spot ofthe first segment can be prevented from being increased due to thezero-order light, and hence the satisfactory detection can be carriedout.

[0114] Furthermore, the present invention includes the laser lightsource for generating the light of laser beams and is arranged so thatthe laser light source may be stopped from generating the light of laserbeams for a fixed time period or longer, provided that the laser lightsource continues emitting the light of laser beams over a predeterminedtime period. Thus, when the application of the light of laser beams tothe object continues, the output of the apparatus can be prevented fromfalling due to produced heat or the like. Therefore, it is possible todispense with the radiator plate and the like which has been used so faras the prior-art countermeasure against heat generation.

[0115] Moreover, according to the present invention, because thehologram reproduced image is projected onto the object, which isobtained by applying the light of laser beams to the arbitrary hologramplate, the hologram reproduced image with sufficient contrast can beprojected onto the object by small power consumption, wherebysatisfactory focusing can be carried out. At the same time, thisapparatus can easily be incorporated into a small electronic stillcamera and the like.

[0116] Furthermore, according to the present invention, the laser driveapparatus including the laser light source for generating the light oflaser beams, the means for adjusting the quantity of light of laserbeams and the camera means further comprises the means for storingtherein the adjustment value found according to the output of the camerameans which takes an image after projecting the light of laser beams.Thus, the output of the laser light source as well as the sensitivity ofthe camera means is adjusted by adjusting the quantity of light of thelaser beams based upon the stored adjustment value, thus enabling suchadjustment that absorbs the dispersions of both the sensitivity ofcamera means and the output of laser light source.

[0117] Moreover, according to the present invention, the hologramreproduced image with sufficient contrast can be projected onto theobject with small power consumption by projecting onto the object thehologram reproduced image which is obtained by applying the light oflaser beams to the hologram plate, so that satisfactory focusing can becarried out. At the same time, this apparatus can easily be incorporatedinto, for example, a small electronic still camera.

[0118] Moreover, according to the present invention, because thequantity of light of laser beams is adjusted based upon the automaticexposure detected value detected from the video signal obtained by thecamera means, the circuit can be diverted to the existing cameraapparatus so that the quantity of light of the laser beams may beadjusted satisfactorily.

[0119] Moreover, according to the present invention, because thequantity of light of laser beams is adjusted based upon the contrastdetected value detected from the video signal obtained by the camerameans, the circuit can be diverted to the existing camera apparatus sothat the quantity of light of laser beams may be adjustedsatisfactorily.

[0120] Furthermore, according to the present invention, because theapparatus includes the laser light source for generating the light oflaser beams and the monitor means for detecting the light of laser beamsand is arranged so that the laser light source may be stopped fromgenerating the light of laser beams on condition that the output of themonitor means exceeds an arbitrary tolerance limit, it is possible toremove the risk that the laser light source may be broken or lessdurable owing to abnormal driving of the laser light source.

[0121] Moreover, according to the present invention, because thehologram reproduced image with sufficient contrast can be projected ontothe object with small power consumption by projecting onto the objectthe hologram reproduced image obtained by applying the light of laserbeams to an arbitrary hologram plate, satisfactory focusing can be done.At the same time, this apparatus can easily be incorporated into a smallelectronic still camera, and the like.

[0122] Furthermore, according to the present invention, the laser driveapparatus includes the laser light source for generating the light oflaser beams and the means for adjusting the quantity of light of laserbeams and is designed to adjust the quantity of light of laser beams bydriving the laser light source according to the pulse signal having thearbitrary pulse width. Thus, the quantity of light of laser beams can beadjusted satisfactorily and also can be adjusted satisfactorilydepending on the presence or absence of the built-in flash device. Atthe same time, it is possible to remove the risk that the laser lightsource may be broken or degraded in durability.

[0123] Moreover, the present invention includes an arbitrary lightingmeans and adjusts the quantity of light of laser beams by controllingthe pulse width of the pulse signal according to in response to thequantity of light of the lighting means. Thus, satisfactory adjustmentof the quantity of light can be made depending on whether the built-inflash device is used or not.

[0124] Moreover, according to the present invention, because there isprovided the means for stopping the laser light source from generatingthe light of laser beams when the means for adjusting the quantity oflight of the laser beams malfunctions, it is possible to remove the riskthat the laser light source may be broken or degraded in durability.

[0125] Furthermore, according to the present invention, because thehologram reproduced image is projected onto the object, which isobtained using the laser light source and the hologram plate, thehologram reproduced image with sufficient contrast can be projected ontothe object with small power consumption, and satisfactory focusing canbe carried out in the auto focus mode of the contrast detection systemor in the manual focus mode. At the same time, this apparatus can easilybe incorporated into, for example, a small electronic still camera.

[0126] Moreover, according to the present invention, because the autofocusing operation is performed by using the projected image of thehologram reproduced image projected onto the object; there can beperformed the extremely satisfactory AF operation.

[0127] Moreover, according to the present invention, because theapparatus includes the operation means for projecting the hologramreproduced image in the manual focus mode, the user can execute theextremely satisfactory manual focusing operation by visually confirmingthe hologram reproduced image, and this hologram reproduced image willnever hinder the user from taking a picture.

[0128] Moreover, according to the present invention, the laser lightsource is stopped from generating the light of laser beams for a fixedtime period or longer on condition that the duration in which the laserlight source continues emitting the light of laser beams exceeds thepredetermined time period. Thus, when the laser light source continuesemitting the light of laser beams for example, the output of theapparatus can be prevented from falling due to produced heat and thelike, so that the radiator plate or the like that has so far been usedas the conventional countermeasure against produced heat can beunnecessary.

[0129] Moreover, according to the present invention, the apparatusincludes the means for adjusting the quantity of light of laser beams,the camera means and the means for storing therein the adjustment valuefound depending on the output of the camera means which takes an imageafter projecting the light of laser beams. Therefore, the output of thelaser light source is adjusted together with the sensitivity of thecamera means by adjusting the quantity of light of laser beams basedupon the above-mentioned adjustment value thus stored, and hence thereis carried out the adjustment which can absorb dispersions of both theoutput of laser light source and the sensitivity of the camera means.

[0130] Moreover, according to the present invention, because thequantity of light of laser beams is adjusted based upon the automaticexposure detected value detected from the video signal obtained when theuser takes a picture by the camera means, the circuit can be diverted tothe existing camera apparatus for satisfactory adjustment of thequantity of light of laser beams.

[0131] Moreover, according to the present invention, because thequantity of light of laser beams is adjusted based upon the contrastdetected value detected from the video signal obtained when the usertakes a picture by the camera means, the circuit can be diverted to theexisting camera apparatus for satisfactory adjustment of the quantity oflight of laser beams.

[0132] Moreover, according to the present invention, because theapparatus includes the monitor means for detecting the light of laserbeams and the laser light source is stopped from generating the light oflaser beams on condition that the output of the monitor means exceeds anarbitrary tolerance limit, there can be removed the risk that the laserlight source may be broken or degraded in durability owing to abnormaldriving of the laser light source.

[0133] Moreover, according to the present invention, because theapparatus includes the means for adjusting the quantity of light oflaser beams and this means adjusts the quantity of light of laser beamsby driving the laser light source with the pulse signal having anarbitrary pulse width, not only the quantity of light of laser beams canbe adjusted satisfactorily, but also the quantity of light of laserbeams can be adjusted depending on whether the built-in flash device isused or not. Thus, there can be removed the risk laser light source willbe broken or that the degraded in durability.

[0134] Moreover, according to the present invention, because theapparatus further includes an arbitrary lighting means and adjusts thequantity of light of laser beams by controlling the pulse widthaccording to the quantity of light of the lighting means, satisfactoryadjustment of the quantity of light of laser beams can be made dependingon whether the built-in flash device is used or not.

[0135] Moreover, according to the present invention, because theapparatus includes the means for stopping the laser light source fromgenerating the light of laser beams when the means for adjusting thequantity of light of laser beams malfunctions, it is possible to removethe risk that the laser light source will be broken or less durable.

[0136] Furthermore, according to the present invention, because thehologram reproduced image, which is obtained by using the laser lightsource and the hologram plate, is projected onto the object and thishologram plate is integrated with the condenser for converting the lightof laser beams into one body unit, the hologram reproduced image withsufficient contrast can be projected onto the object so thatsatisfactory focusing may be made. At the same time, even if thehologram plate is detached from the laser diode, it will be possible toremove such a risk that a man as the object may feel discomfort due tothe dazzling light of laser beams.

[0137] Moreover, according to the present invention, because the autofocusing operation is performed by using the projected image of thehologram reproduced image projected onto the object, the extremely goodAF operation can be carried out.

[0138] Furthermore, according to the present invention, because theapparatus includes the operation means for projecting the hologramreproduced image in the manual focus mode, a user can execute theextremely good manual focusing operation by visually confirming thehologram reproduced image. Then, this hologram reproduced image willnever hinder the user from taking a picture.

[0139] As described above, when a user takes a picture by a stillcamera, for example, in the dark, it is very difficult for the user tofocus on the object in the auto focus mode of the contrast detectionsystem or in the manual focus mode. On the other hand, the conventionalcamera apparatus using the auxiliary floodlight cannot focus on theobject sufficiently. Moreover, because this apparatus has large powerconsumption, it cannot be incorporated into a small electronic stillcamera and the like. In addition, when the hologram plate is detachedfrom the laser diode, there is the risk that a man as the object mayfeel uncomfortable very much if he sees the dazzling light of parallellaser beams. According to the present invention, these problems can beovercome with ease.

1. An image projection apparatus comprising a laser light source forgenerating light of laser beams and a hologram plate, wherein said imageprojection apparatus applies said light of laser beams to said hologramplate to obtain a hologram reproduced image and projects said hologramreproduced image onto an object.
 2. An image projection apparatusaccording to claim 1, wherein said image projection apparatus performsan auto focusing operation by using a projected image of said hologramreproduced image projected onto said object.
 3. An image projectionapparatus according to claim 1, further comprising operation means forprojecting said hologram reproduced image in a manual focus mode.
 4. Animage projection apparatus comprising: a laser light source forgenerating light of diffused laser beams; a condenser for convertingsaid light of diffused laser beams to light of parallel laser beams; anda hologram plate irradiated with said light of parallel laser beams,wherein said condenser is integrated with said hologram plate into onebody unit.
 5. An image projection apparatus according to claim 4,wherein said image projection apparatus applies said light of parallellaser beams to said hologram plate to obtain a hologram reproduced imageand projects said hologram reproduced image onto an object.
 6. An imageprojection apparatus according to claim 5, wherein said image projectionapparatus performs an auto focusing operation by using a projected imageof said hologram reproduced image projected onto said object.
 7. Aprojection image pattern projected by an image projection apparatuscomprising a laser light source for generating light of laser beams anda hologram plate, wherein: at least first to fifth segments arecomprised of one or a plurality of segments, each segment including apredetermined number of light spots arrayed in a straight line; saidfirst segment is provided in the center of a projected image at an angleof approximately 45 degrees with horizontal and vertical axes of animage pickup plane; four said second segments are provided, at rightangles with said first segment, at each vertex of a square thatcircumscribes a circle centered at the center of said first segment andhas a predetermined length of diameter; eight said third segments areprovided, in parallel with said first segment, at each vertex and at amidpoint in each side of a square that circumscribes a circle centeredat the center of said first segment and has a diameter twice thepredetermined length; twelve said fourth segments are provided, at rightangles with said first segment, at each vertex and at points trisectingeach side of a square that circumscribes a circle centered at the centerof said first segment and has a diameter three times the predeterminedlength; four said fifth segments are provided, in parallel with saidfirst segment, at a midpoint of each side of a square that circumscribesa circle centered at the center of said first segment and has a diameterfour times the predetermined length.
 8. A projection image patternaccording to claim 7, wherein the central light spot is removed fromsaid predetermined number of light spots forming said first segment. 9.A laser drive apparatus comprising a laser light source for generatinglight of laser beams, wherein said laser drive apparatus stops saidlaser light source from generating said light of laser beams for a fixedtime period or longer on condition that said light of laser beams iscontinuously generated over a predetermined time period.
 10. A laserdrive apparatus according to claim 9, wherein a hologram reproducedimage is obtained by applying said laser beams to an arbitrary hologramplate and said hologram reproduced image is projected onto an object.11. A laser drive apparatus including a laser light source forgenerating light of laser beams, means for adjusting a quantity of saidlight of laser beams, and camera means, wherein means for storingtherein an adjustment value found according to an output of said camerameans which takes a picture after projecting said light of laser beamsis provided, and the quantity of said light of laser beams is adjustedbased upon said stored adjustment value.
 12. A laser drive apparatusaccording to claim 11, comprising means for projecting onto an object ahologram reproduced image that is obtained by applying said laser beamsto an arbitrary hologram plate.
 13. A laser drive apparatus according toclaim 11, wherein said adjustment means adjusts a quantity of said lightof laser beams based upon an automatic exposure detected value detectedfrom a video signal obtained when said camera means takes a picture. 14.A laser drive apparatus according to claim 11, wherein said adjustmentmeans adjusts a quantity of said light of laser beams based upon acontrast detected value detected from a video signal obtained when saidcamera means takes a picture.
 15. A laser drive apparatus comprising alaser light source for generating light of laser beams and monitor meansfor detecting said light of laser beams, wherein said laser driveapparatus stops said laser light source from generating said light oflaser beams on condition that an output of said monitor means exceeds anarbitrary tolerance limit.
 16. A laser drive apparatus according toclaim 15, wherein a hologram reproduced image that is obtained byapplying said light of laser beams to an arbitrary hologram plate isprojected onto an object.
 17. A laser drive apparatus comprising a laserlight source for generating light of laser beams and means for adjustinga quantity of said light of laser beams, wherein said adjustment meansadjusts the quantity of said light of laser beams by driving said laserlight source through a pulse signal having an arbitrary pulse width. 18.A laser drive apparatus according to claim 17, further comprisinglighting means, wherein said adjustment means adjusts a quantity of saidlight of laser beams by controlling said pulse width according to aquantity of light of said lighting means.
 19. A laser drive apparatusaccording to claim 17, further comprising means for stopping said lightsource from generating said light of laser beams when said adjustmentmeans for adjusting a quantity of said light of laser beamsmalfunctions.
 20. A camera apparatus comprising an image projectionapparatus that includes a laser light source for generating light oflaser beams and a hologram plate, wherein said camera apparatus projectsonto an object a hologram reproduced image obtained by applying saidlight of laser beams to said hologram plate.
 21. A camera apparatusaccording to claim 20, wherein an auto focusing operation is performedby using a projected image of said hologram reproduced image projectedonto said object.
 22. A camera apparatus according to claim 20, furthercomprising operation means for projecting said hologram reproduced imageonto the object in a manual focus mode.
 23. A camera apparatus accordingto claim 20, wherein said laser light source is stopped from generatingsaid light of laser beams for a fixed time period or longer on conditionthat said light of laser beams is generated continuously over apredetermined time period.
 24. A camera apparatus according to claim 20,comprising means for adjusting a quantity of said light of laser beams,and camera means, wherein means for storing therein an adjustment valuefound according to an output of said camera means which takes a pictureafter projecting said light of laser beams is provided, and saidadjustment means adjusts a quantity of said light of laser beams basedupon said stored adjustment value.
 25. A camera apparatus according toclaim 20, wherein said adjustment means adjusts a quantity of said lightof laser beams based upon an automatic exposure detected value detectedfrom a video signal obtained when said camera means takes a picture. 26.A camera apparatus according to claim 20, wherein said adjustment meansadjusts a quantity of said light of laser beams based upon a contrastdetected value detected from a video signal obtained when said camerameans takes a picture.
 27. A camera apparatus according to claim 20,further comprising monitor means for detecting said light of laserbeams, wherein said laser light source is stopped from generating saidlight of laser beams on condition that an output of said monitor meansexceeds an arbitrary tolerance limit.
 28. A camera apparatus accordingto claim 20, comprising means for adjusting a quantity of said light oflaser beams, wherein said adjustment means adjusts a quantity of saidlight of laser beams by driving said laser light source using a pulsesignal having an arbitrary pulse width.
 29. A camera apparatus accordingto claim 28, further comprising arbitrary lighting means, wherein saidadjustment means adjusts a quantity of said light of laser beams bycontrolling said pulse width according to a quantity of light of saidlighting means.
 30. A camera apparatus according to claim 28, comprisingmeans for stopping said laser light source from generating said light oflaser beams when said adjustment means for adjusting a quantity of saidlight of laser beams malfunctions.
 31. A camera apparatus comprising animage projection apparatus that includes a laser light source forgenerating light of diffused laser beams, a condenser for convertingsaid light of diffused laser beams to light of parallel laser beams, anda hologram plate irradiated with said light of parallel laser beams,said condenser being integrated with said hologram plate into one bodyunit, wherein said image projection apparatus projects onto an object ahologram reproduced image that is obtained by applying said light ofparallel laser beams to said hologram plate.
 32. A camera apparatusaccording to claim 31, wherein an auto focusing operation is performedby using a projected image of said hologram reproduced image projectedonto said object.
 33. A camera apparatus according to claim 31, furthercomprising operation means for projecting said hologram reproduced imageonto the object in a manual focus mode.